One of the most pressing questions in neuroscience is how an organism is able to represent information about the outside world in patterns of spike trains throughout a network of neurons. I propose to investigate this question in the rat whisker somatosensory system, by looking at the first phase in the process of information transformation from the outside world to the animal's nervous system - the transduction of mechanical stimuli obtained during whisking into patterns of action potentials in the first order, primary afferent cells of the trigeminal ganglion. The experiments I propose will shed light on the coding mechanisms that the animal uses to represent different aspects of stimuli it contacts during natural whisking behavior. Specifically, my hypotheses are: (1) The activity patterns of a trigeminal primary afferent can accurately encode stimulus features associated with a single whisker contact, and (2) Trigeminal ganglion cells use a high fidelity temporal code to represent this single contact information. [unreadable] [unreadable]